A relatively large variety of yard and garden tractors are utilized by home owners to carry and power a wide variety of attachments such as rotary lawn mowers, spreaders, sprayers, rollers, aerators, plows, cultivators, harrows, rotary spaders, seed planters, and snow blowers. Many of these devices incorporate rotary tools which require a driving force that is usually provided by a primary power take-off from the tractor engine. A primary example of such devices is the rotary lawn cutting attachment commonly used to convert yard and garden tractors into riding lawn mowers.
Riding lawn mowers which are specifically designed as such or which are converted yard and garden tractors produce a large volume of grass clippings which must be removed from lawns to prevent a heavy thatch of clippings from building up which will smother new grass growth, provide a hiding place for destructive insects and provide an environment suitable for the rapid growth of mold, fungus and other lawn diseases. The removal of grass clippings has been accomplished by a variety of techniques ranging from a manual rake to an elaborate vacuum cleaning system. The manual rake functions satisfactorily for a relatively small area but when large grass tracks are groomed, that method is not practical. For large tracks, tractor powered mowers normally utilize a relatively sophisticated vacuum or vacuum and sweeper devices.
An example of a prior art means for removing grass clippings produced by a tractor type lawn mower is presented in U.S. Pat. No. 3,903,565 on "Leaf And Grass Cart Bagger" issued to Littleberry T. Hicks on Sept. 9, 1975. This patent discloses a refuse container mounted in a small trailer adapted to be pulled by the grass mowing tractor. Clippings are transported from the cutting area to the refuse container via a duct vacuum transport which utilizes a blower powered by some unknown means. Presumably the blower is driven by an auxiliary internal combustion engine in a manner similar to that illustrated on Page 10 of the 1976 Yard and Garden Tractors and Attachments Catalog prepared by Sears, Roebuck & Company.
The use of an auxiliary internal combustion engine to drive a blower is undesirable for it tends to increase the complexity and cost of the grass clipping collection system. Furthermore it is an inefficient waste of petroleum products which is to be avoided in view of the constant threat of fossil fuel supply exhaustion.
Trailer systems such as the Hicks system discussed above are not satisfactory when mowing around flower beds and similar areas for as the tractor rounds the corner, the trailer will turn in an arc which will cause the wheels to destroy the corner portions of the flower bed or other structure which is being circumnavigated. In some instances, such as going around the corners of buildings, the tractor has to swing wide to prevent the trailing grass catcher from striking the corners of the building and thus the grass close to the building cannot be mowed.
S. E. Clarke in U.S. Pat. No. 3,203,022 on "Vacuum Cleaner For Lawns" issued Aug. 31, 1965 suggests a way to eliminate the need for an auxiliary internal combustion engine for powering the blower in a vacuum lawn sweeper. Unfortunately this system can be used only with vehicles having a rear wheel differential gear train that incorporates a power take-off shaft. This adds significantly to the cost of the vehicle and renders the vacuum cleaner attachment a very special purpose device fabricated for a specific type of tractor and not one which is normally found in the yard and garden market. Note that the Clarke device also incorporates a separate vacuum nozzle that adds significantly to the complexity and cost of producing the device and that it further requires a wheeled dolly to support the refuse container. The shortcomings of the wheeled dolly are similar to those discussed for the wheeled cart above.
James F. Peterson, U.S. Pat. No. 4,047,368 on "Attachment For Collecting Mower Discharge In A Plurality Of Bags" issued Sept. 13, 1977 is an example of a vacuum lawn sweeper similar to the Clarke device in that power is derived from a take-off associated with the rear wheel drive differential of the tractor. Here, as in Clarke, special adaptations to the tractor drive train must be provided to enable power to be transferred from the vehicle to the blower impeller. Also, devices such as this only provide power to the blower while the vehicle is in motion.
The various problems suggested are partially solved by the apparatus disclosed in the co-pending U.S. Pat. No. 4,104,852 of DeForrest Tackett on "Lawn Clipping Vacuum Collector" filed Nov. 8, 1976 and issued as U.S. Pat. No. 4,104,852. This co-pending patent application discloses a vacuum collector which is supported at the back of a riding lawn mower and driven by a belt drive system which couples energy from the rotary lawn mower drive shaft to the vacuum blower impeller.
All of the known prior art devices exemplified in the foregoing examples require a special purpose power take-off to drive the blower which is relatively complex and in most instances includes moving parts having relatively short useful lives such as drive belts or else they require an additional motive source such as an auxiliary engine. These shortcomings in lawn clipping vacuum collectors are also present in every type of tractor lug which includes a driven rotary tool.